soluble

The story

1. Latin · derived fromsolvere“to loosen”
2. Late Latin · derived fromsolūbilis
3. Old French · derived fromsoluble
4. Middle English · inherited fromsoluble
5. English todaysoluble

From Middle English soluble, from Old French soluble, from Late Latin solūbilis, from Latin solvere (“to loosen”) + -bilis. Piecewise doublet of solvable.